1. Field of the Invention
This invention relates to a condition monitoring system for monitoring the condition of a self-propelled machine, and also to a condition monitoring system unit and terminal system unit useful in the condition monitoring system.
2. Description of the Related Art
Working machines (self-propelled machines) used in mines and the like, such as excavators and dump trucks, are required to operate for 24 hours a day. Working machines of this kind are provided with a controller and various sensors. The controller monitors whether or not sensor data inputted from the various sensors or processed data obtained by processing the sensor data have normal values. If at least one of the sensor data or processed data exceeds a corresponding threshold value set as a condition for delivering an alarm, the controller delivers an alarm to urge an operator to maintain a normal condition. Further, the information of the alarm is transmitted, via a radiocommunication system, from a terminal system unit on the working machine to a condition monitoring system unit arranged in a control room. A supervisor understands the condition of the working machine by confirming alarm information displayed on a control screen of a condition monitoring system unit. It is, therefore, important to set a suitable condition for the delivery of an alarm.
As a technology for setting such a suitable condition for the delivery of an alarm, JP-A-2011-147493 is known, for example. JP-A-2011-147493 describes: “On a screen with a trend graph, which indicates historical data of biological information, being displayed thereon, a biological information monitoring system receives from a user an input of an alarm value about the biological information. When the alarm value is inputted, ranges Tb1,Tb2 where an alarm is to be triggered are displayed in the trend graph according to the inputted alarm value (upper limit line: Lb1, lower limit line: Lb2) such that the ranges Tb1,Tb2 can be distinguished from other ranges. If the alarm value has already been set in the past, the ranges Tb1,Tb2 where an alarm is to be triggered by the new alarm value are displayed, in the trend graph, distinguishably from ranges Ta1,Ta2 where an alarm was actually triggered.” (see the Abstract).